Blackout fabric is used primarily to block light. It is a lining fabric, used along with another fabric to form draperies, curtains or other window treatments. Blackout fabric can also provide insulation against outdoor temperatures, reducing heating and cooling costs. Sewing with blackout fabric can be challenging, but the rewards are significant in terms of function and comfort in your home.
Cut blackout fabric with sharp sewing scissors or a rotary cutter, mat and ruler. Use weights rather than pins to prevent pinholes in the rubbery blackout lining fabric. Cut blackout fabric slightly narrower and shorter than the outer drapery fabric.
Stitch together widths of blackout fabric to create the width required for your window. Sew a neat 1.6 cm (5/8 inch) seam with a straight stitch on your sewing machine. Press to one side with a dry iron on a medium heat setting. Topstitch the seam allowances on one side.
Press a doubled hem under at the bottom of the blackout lining. Turn under a narrower hem at each side. Iron deeper hems into the outer curtain fabric.
Tuck the lining into the outer fabric hems, lining up the folded edges. Face the hem allowance of the blackout lining toward the wrong side of the outer curtain fabric. Encase the hems of the blackout drapery lining in the hems of the outer fabric. Sew the three sides of the blackout fabric and outer fabric together by hand or machine.
Press the top edge of both the outer fabric and blackout fabric under. Sew to form a wide rod pocket or a neat hem. Sew pleating tape or other drapery notions into place through both the blackout fabric and curtain fabric.
Add an interlining for additional warmth in your blackout curtains.